import sys
sys.setrecursionlimit(10**7)

def input(): return sys.stdin.readline()[:-1]
mod = 10**9 + 7
def readInt():return int(input())
def readIntList():return list(map(int,input().split()))
def readStringList():return list(input())
def readStringListWithSpace():return list(input().split())
def readString():return input()

x = readInt()
print("Yes" if x >= 30 else "No") import sys sys sys.setrecursionlimit(10**7) sys.setrecursionlimit sys setrecursionlimit 10**7 10 7 def input(): return sys.stdin.readline()[:-1] input mod = 10**9 + 7 mod 10**9 + 7 10**9 10 9 7 def readInt():return int(input()) readInt def readIntList():return list(map(int,input().split())) readIntList def readStringList():return list(input()) readStringList def readStringListWithSpace():return list(input().split()) readStringListWithSpace def readString():return input() readString x = readInt() x readInt() readInt print("Yes" if x >= 30 else "No") print "Yes" if x >= 30 else "No" x >= 30 x 30 "Yes" "No" def readStringListWithSpace():return list(input().split()) def readStringListWithSpace():return list(input().split()) readStringListWithSpace def readInt():return int(input()) def readInt():return int(input()) readInt def readStringList():return list(input()) def readStringList():return list(input()) readStringList def input(): return sys.stdin.readline()[:-1] def input(): return sys.stdin.readline()[:-1] input mod = 10**9 + 7 10**9 + 7 mod def readString():return input() def readString():return input() readString x = readInt() readInt() x def readIntList():return list(map(int,input().split())) def readIntList():return list(map(int,input().split())) readIntList
import sys
sys.setrecursionlimit(10**7)

def input(): return sys.stdin.readline()[:-1]
mod = 10**9 + 7
def readInt():return int(input())
def readIntList():return list(map(int,input().split()))
def readStringList():return list(input())
def readStringListWithSpace():return list(input().split())
def readString():return input()

x = readInt()
print("Yes" if x >= 30 else "No")